where \(m_n\)  is the Nakagami-\(m\)  fading parameter between the \(n\) th
successful relay and the destination. For example, if the first and
the second relays out of three relays successfully decode the
information from \(U_l\) , we have \(m_1=m_{1d}\)  and \(m_2=_{2d}\) . Using
Fourier transform together with [1]}, the characteristic function (CF)
of \(Y_n\)  is calculated as
\(\begin{split}C_{Y_n } \left( u \right) &= \int _{-\infty }^\infty {f_{Y_n}\left(y\right)e^{juy}dy}=\left( {1 - \frac{{jua_n }}{m_n}} \right)^{ - m_n}.\end{split}\) 
